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Juniper Junos OS Vulnerability (JSA83021)

medium Nessus Plugin ID 310748

Synopsis

The remote device is missing a vendor-supplied security patch.

Description

The version of Junos OS installed on the remote host is affected by a vulnerability as referenced in the JSA83021 advisory.

 - An Improper Check for Unusual or Exceptional Conditions vulnerability in the flow daemon (flowd) of Juniper Networks Junos OS on SRX4600 and SRX5000 Series allows an attacker to send TCP packets with SYN/FIN or SYN/RST flags, bypassing the expected blocking of these packets. A TCP packet with SYN/FIN or SYN/RST should be dropped in flowd. However, when no-syn-check and Express Path are enabled, these TCP packets are unexpectedly transferred to the downstream network. This issue affects Junos OS on SRX4600 and SRX5000 Series: * All versions before 21.2R3-S8, * from 21.4 before 21.4R3-S7, * from 22.1 before 22.1R3-S6, * from 22.2 before 22.2R3-S4, * from 22.3 before 22.3R3-S3, * from 22.4 before 22.4R3-S2, * from 23.2 before 23.2R2, * from 23.4 before 23.4R1-S1, 23.4R2. (CVE-2024-39561)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Apply the relevant Junos software release referenced in Juniper advisory JSA83021

See Also

http://www.nessus.org/u?fed0e234

Plugin Details

Severity: Medium

ID: 310748

File Name: juniper_jsa83021.nasl

Version: 1.1

Type: Combined

Published: 4/28/2026

Updated: 4/28/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 1.6

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2024-39561

CVSS v3

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 5.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Vulnerability Information

CPE: cpe:/o:juniper:junos

Required KB Items: Host/Juniper/model, Host/Juniper/JUNOS/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 7/10/2024

Vulnerability Publication Date: 7/10/2024

Reference Information

CVE: CVE-2024-39561

JSA: JSA83021